One magazine did call her his fiancee instead of his girlfriend, so it looks like they just might be. I haven't seen it in other magazines.

And yeah, I saw that ring! I'm actually hoping they are engaged because good for them, especially since they've been together for 5 years already. (There's also speculation about the fact that he's been wearing a gold band on his ring finger. I kind of love fandom for the "Are they already married and just waiting to announce it and making it look like they're engaged for now or is that a promise ring or just a regular ring?" talk. LOL.)